Fuel supply system



E. O. WIRTH Aug. 25, 1942.

FUEL SUPPLY SYSTEM Filed July 20, 1940 2 Sheets-Sheet l INVENTOR Emu. O.WIRTH ATTORNEY Aug. 25; 1942. E. o. WIRTH 2,294,326

FUEL SUPPLY SYSTEM Filed July 20, 1940 2 sh ets-sh et 2 IO ,5: 5624 54 42 E. I I6 I? 2 50 l 48 Li as V Y v 25 I 48 FIG. 4 v

INVENTOR EM/L. 0. W/RTH a 5520mm Patented Aug. 25, 1942 UNITED" STATES PATENT. OFFICE FUEL SUPPLY SYSTEM Emil 0. Wirth, South Bend, Ind., assignor to Bendix Aviation Corporation, South Bend, Indl, a corporation of Delaware Application July 20, 1940, Serial No. 346,483

13 Claims. (Cl. 123-122)- This invention relates generally to fuel supply systems, and particularly to intake manifolds for internal combustion engines.

The trend of modern automobile design is to lower the hood, and in some automobiles it has been lowered to such an extent that little space remains above the level of the top of the engine for the downdraft type of carburetor and its air filter which extend a considerable distance above such engine-top level. It has become a particularly diflicult problem to use the downdraft type of carburetor on automobile engines having overhead valves where the hood level has been lowered to an extreme degree in accordance with modern design, engines of this type having a somewhat greater overall vertical dimension than those of the L-head type.

A further complication of the problem arises in connection with internal combustion engines having such number of in-line cylinders as to require a dual or multiple intake manifold wherein a long and a short main fuel conduit is used. The straight eight-cylinder engine is an example of the type using a dual intake manifold of this character in which each conduit is provided with its own inlet and a twin throttle barrel carburetor is used.

In order to avoid returning to the use of the -updraft type of carburetor, with its inherent disadvantages, for engines of automobiles havin hoods so low there is insufficient room for a downdraft carburetor above the top level of the engine, the present invention proposes to alter the construction of the intake manifold so that it may receive and advantageously cooperate with a horizontal twin throttle barrel carburetor of special construction. One type of such a carburetor is disclosed in the copending application of Emil O. Wirth and George P. Lum for a Charge forming device, filed July 20, 1940, and bearing Serial No. 346,510.

In intake manifolds of the above described character, one main conduit is longerthan the other and it has been found that the fuel mixture passing through the longer conduit becomes much cooler before it reaches the cylinders to which it is traveling than the fuel mixture in the short conduit. This is due primarily to the greater distance it must traverse after the initial heating thereof by the heater or hot spot, and the present invention provides means to compensate for this inequality.

With the foregoing in view it is an important object of my invention to provide a horizontal intake manifold having a plurality of primary 55 fuel conduits each of which has an inlet the axis of which is horizontal, the device being adapted to have a horizontal twin carburetor operably attached thereto.

Another object of my invention is to provide a manifold of this character wherein the axes or the centers of said inlets are in the same horizontal plane- A further object of the invention is to provide a manifold of this character wherein the zones of heat-of the heater for the conduits varies with the length of said conduits.

A still further object of the invention is to provide a device of this character wherein one of the primary conduits is higher than the other.

Numerous other objects and advantages of the invention will be apparent from the following de tailed description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

Figure 1 is a side elevational view of a mani+ take manifold having a long horizontal conduit and a short horizontal conduit, each of which comprise oppositely disposed branches numbered respectively l0 and I2, and M and Hi. The branches of each conduit are axially aligned and the conduits extend parallel with each other.

The long conduit is provided with an inlet l8 and the short conduit is provided with an inlet 20, the axes of said inlets being in the same horizontal plane, which plane, in the illustrated embodiment, also includes the axis of the short conduit. Passages 22 and 2d lead from the respective inlets to the respective long and short conduits, and communicate therewith, passage 22 taking a downwardly inclined course and passage 24 a horizontal course due to the short conduit being higher than the long one. The short conduit is also spaced rearwardly of the other conduit in order to provide room for the passage 22. This particular embodiment of the invention conduit portion than that in and by the time said mixture reaches the cylinis adapted for use on an in-line eight-cylinder engine 25 such as is shown in Figure 4, although it is to be distinctly understood that the invention is not confined to use on an eight-cylinder engine of this character but may be used on engines having other characteristics. I

, Laterally extending outlets 2B, 28, 30 and 32 are provided adjacent the ends of the respective branches and the free ends thereof are adapted to register with the respectiveinlet ports of the internal combustion engine 25 to which the manifold is attached ,as shown in Figure 4. The exhaust manifold 36 of the engine is secured thereto by the same means that secures the intake manifold; said means comprising bolts 38 fixed in the block of the engine 25 and washers 40 on said bolts engaging lugs 42 on the respective outlets of the intake manifold and lugs 44 on inlets 46 of the exhaust pipe. The manifolds are drawn tight by nuts 58 on the bolts 38. For tightly securing the outlets 26 and 32 of the intake manifold and the respective end inlets of the exhaust manifold clamp members 58 are used in place of the washers 40, this being conventional practice. However, any other suitable meansfor attaching the manifolds to the engine may be employed.

In an-engi'ne of the straight eight type, each branch of the manifold supplies fuel to two cylinders through the respective outlets. More particularly, and considering the cylinders from front to rear, branches IO, N, l8 and I2 feed cylinders I and 2, 3 and B, and 6, and I and 8, respectively.

To heat the fuel mixture passing through the conduits, a hot spot or stove is provided integral with the conduits. Heating chamber 5! of the stove encases passages 22 and 24 and adjacent portions of the conduits, the upper section 52 of the stove providing a zone of heat along 2. limited portion of the short conduit and lower section 55 of the stove providing a more extensive zone of heat about the longer conduit. Thus the fuel mixture passing through the long conduit is initially heated by the stove to a higher temperature than that in the short conduit. Howeve the mixture in the long conduit travels a greater distance in a substantially unheated the short conduit ders to which it is going it has cooled so that its temperature is substantially the same as that reaching the cylinders from the short conduit. In other words the temperatureof the fuel mixture reaching the respective cylinders is substantially uniform.

The intake and exhaust manifolds are secured together by bolts, not shown, passing through holes 56 formed in ears 58 on the intake manfold, and holes 68, the stove or hot spot being connected with the exhaust manifold in the conventional manner to be heated by exhaust gases from the latter entering the stove through opening 6|. However, other means for connecting the intake and exhaust manifolds may be employed.

It is the practice of some automobile manufacturers to mount the engine at an angle so that the front end is higher than the rear. This inclination of the engine is shown in Figure 4.

However; to provide proper distribution of the fuel mixture to the cylinders and to mount the carburetor in a manner to maintain the normal fuel level therein it is desirable that-the primary conduits of the manifold be horizontal as shown and described herein. With the primary conduits of the manifold horizontal, the respective outlets of the intake manifold will vary in length, the outlets being progressively longer from front to rear of the manifold as particularly shown in Figures 1 and 4.

A horizontal twin barrel carburetor 62 is secured to the intake manifold by bolts 64 screwed into openings 66 of the manifold, one throttle barrel of the carburetor supplying fuel to one of the inlets of the intake manifold and the other barrel supplying fuel to the other mani fold inlet.

It is thought that the invention and many of its attendant advantages will be readily understood from the foregoing description and though said invention has been illustrated and described with reference to a single embodiment it will be apparent that various changes may be made in 20' the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. In an intake manifold for internal combustion engines, a plurality of conduits, one of said conduits being disposed higher than the other, each of said conduits having an inlet with communicating means therewith, and the axes'of said inlets being in the same horizontal plane and above the horizontal plane of the axis of the lower conduit.

2. In an intake manifold for internal combustion engines, a plurality of horizontal branched conduits, the branches of one conduit being shorter and higher than the branches of the other conduit and'spaced rearwardly relative thereto. there being an inlet for each conduit, said inlets having their axes in substantially the same horizontal plane as the axis of the upper conduit, means connecting each inlet with its respective conduit, and outlets for the respective branches of the conduits.

3. In an intake manifold for an in-line eightcylinder internal combustion engine, a long substantially horizontal conduit having an outlet adjacent each end for supplying fuel to respectivegroups of cylinders, and a short substantially horizontal conduit having an outlet adjacent each end for supplying fuel respectively to other groups of cylinders, one of said conduits being higher than the other and each conduit'havin an inlet communicating therewith, the axes of said inlets being in substantially the same horizontal plane and having an elevation at least equal to that of the axis of the higher of said conduits. 7 v

4. In a fuel supply system for an in-line eightcylinder internal combustion engine, a long substantially horizontal conduit having. an outlet adjacent each end for supplying fuel to respective groups of cylinders, a short substantially horizontal conduit having an outlet adjacent each end for supplying fuel respectively to other groups of cylinders, each of said conduits having an inlet, the axes of the inlets being in substantially the same horizontal plane, and a mixture through a major portion of its length and having outlets at either end adapted to feed mixture to the first and fourth pairs of cylinders respectively, a second mixture conduit extending in a horizontal plane through a portion of its length and having outlets at either end adapted to feed mixture to the second and third pairs of cylinders respectively, and a pair of closely adjacent mixture passages extending transversely of said conduits and respectively communicating with the conduits intermediate their ends, the inlets to said passages having their axes in the same horizontal plane, at least one of said mixture passages being inclined downwardly from the respective inlet thereof.

6. In an intake manifold for an internal combustion engine, a plurality of mixture conduits each of which is provided with an inlet, outlets from said conduits for delivering mixture to the engine, one of said conduits being shorter than the other, and means for heating the mixture in said conduits to provide substantially uniform mixture temperatures at the conduit outlets, said heating means extending throughout a portion only of the lengthspf the respective conduits, a greater zone of heat being provided for the long conduit than for the short one.

7. In an intake manifold for an internal combustion engine, a plurality of horizontal mixture conduits, one of the conduits being longer than the other and one of said conduits being higher than the other, each of said conduits being provided with an inlet the axis of which is horizontal, outlets. from said conduits, and heating means for said conduits whereby said conduits are heated throughout a limited portion of their respective lengths, the short conduit having a shorter heating means than the other conduit to provide substantially uniform mixture tempera tures at the conduit outlets.

8. An intake manifold for internal combustion engines, including a long conduit and a short substantially horizontal conduit, the latter being higher than the former, heating means adapted to receive heat from a suitable source, and to heat said conduits throughout a portion of their respective lengths, the longer conduit having a greater portion of its length heated than the shorter one, outlets for said conduits, and an inlet for each of said conduits, the center of said inlets being in substantially the same horizontal plane as the axis of the higher conduit.

9. An intake manifold for an internal combustion engine, including a plurality of conduits of varying length, and heating means extending over only a portion of the lengths of said conduits and varying according to the length thereof, each of said conduits having an inlet, the axes of said inlets being in the same horizontal plane.

10. An intake manifold for a straight eightcylinder internal combustion engine having an exhaust manifold, a long conduit and a short conduit, one of said conduits being higher than the other, heat jackets for said conduits extending throughout a portion only of their respective lengths, the jacket for the long conduit extending further along same than the other jacket extends along the short conduit, the spaces enclosed by the jackets being connected with the exhaust manifold, each of the conduits having an inlet with a horizontal axis, and an outlet adjacent the respective ends of each conduit adapted to supply respective groups of cylinders of the engine with fuel.

11. The invention defined in claim 10 combined with a horizontal double-barreled carburetor.

12. The combination of an in-line eight-cylinder engine having an exhaust manifold, an intake manifold comprising a short horizontal conduit and a long horizontal conduit lower than the short conduit, an outlet adjacent the respective ends of each conduit, each successive-outlet supplying successive pairs of cylinders with fuel, each conduit having an inlet and communicating passage, the centers of the inlets being in 'substantially the same horizontal plane as the axis of the short conduit.

13. In an integral dual intake manifold for an internal combustion engine having an exhaust manifold, comprising a long substantially horizontal conduit and a short substantially horizontal conduit, each conduit having outlets and one of said conduits being higher than the other,

closely adjacent inlets and connecting passages for the respective conduits, the axes of said inlets being in the same horizontal plane as the axis of the higher conduit, and a heat jacket connected with the exhaust manifold and encasing said passages and extending along the conduits for a portion of their lengths respectively whereby said portions of the conduits are exposed to hot exhaust gases, said jacket extending a greater distance along the long conduit than along the short conduit. V

' EMIL O. WIR'I'H. 

